ETSI TS 102 345-2008 Corporate telecommunication Networks (CN) Tunnelling of QSIG over SIP (V1 3 1)《共同通信网络(CN) SIP上的QSIG隧道效应 (版本1 3 1)》.pdf

1、 ETSI TS 102 345 V1.3.1 (2008-10)Technical Specification Corporate telecommunication Networks (CN);Tunnelling of QSIG over SIPETSI ETSI TS 102 345 V1.3.1 (2008-10)2Reference RTS/ECMA-00351 Keywords IP, PISN, QSIG, signalling ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +

2、33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice Individual copies of the present document can be downloaded from: http:/www.etsi.org The present document may be made avai

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7、and of the 3GPP Organizational Partners. ETSI ETSI TS 102 345 V1.3.1 (2008-10)3Contents Intellectual Property Rights 5g3Foreword . 5g3Introduction 5g31 Scope 6g32 Normative references . 6g33 Terms and definitions . 7g33.1 External definitions 7g33.2 Other definitions . 7g33.2.1 Corporate telecommuni

8、cation Network (CN) . 7g33.2.2 Egress gateway . 7g33.2.3 Gateway 7g33.2.4 Ingress gateway 7g33.2.5 IP network . 7g33.2.6 Media stream 7g33.2.7 Private Integrated Services Network (PISN) 8g33.2.8 Private Integrated services Network eXchange (PINX) . 8g34 Abbreviations and acronyms 8g35 Background and

9、 architecture 8g35.1 Architecture 8g35.2 Basic operation . 9g35.3 QSIG connectionless transport . 10g35.4 Late availability of SDP parameters at the egress gateway 10g36 Procedures 10g36.1 General . 10g36.2 Encapsulation of QSIG messages in SIP messages 10g36.3 QSIG SETUP message handling at an ingr

10、ess gateway . 11g36.3.1 Sending a SIP INVITE request . 11g36.3.2 Receipt of responses to the INVITE request . 11g36.4 QSIG SETUP message handling at an egress gateway 12g36.4.1 Receiving a SIP INVITE request 12g36.4.2 Rejecting a QSIG message in an INVITE request 13g36.5 Subsequent QSIG messages . 1

11、3g36.6 Terminating the SIP dialog . 13g36.7 QSIG connectionless message handling at an ingress gateway 13g36.7.1 Sending a SIP INVITE request . 14g36.7.2 Receipt of responses to the INVITE request . 14g36.8 QSIG connectionless message handling at an egress gateway . 14g37 Example message sequences 1

12、5g37.1 Call establishment 15g37.2 Call clearing . 16g37.3 QSIG connectionless message 17g37.4 Call establishment with port=0 in first SDP answer . 17g37.5 Backwards compatibility with early editions . 19g38 Security considerations. 21g3Annex A (informative): Changes from early editions . 22g3A.1 Mot

13、ivation for changes in payload renegotiation procedures 22g3A.2 Late availability of SDP parameters at the egress gateway 22g3A.3 Compatibility with gateways that support early editions of this standard 23g3ETSI ETSI TS 102 345 V1.3.1 (2008-10)4History 24g3ETSI ETSI TS 102 345 V1.3.1 (2008-10)5Intel

14、lectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Righ

15、ts (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IP

16、R searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This Technical Specification (TS) has been

17、produced by ECMA on behalf of its members and those of the European Telecommunications Standards Institute (ETSI). Introduction The present document is one of a series of Ecma Standards defining the interworking of services and signalling protocols deployed in corporate telecommunication networks (C

18、Ns) (also known as enterprise networks). The series uses telecommunication concepts as developed by ITU-T and conforms to the framework of International Standards on Open Systems Interconnection as defined by ISO/IEC. This particular Standard specifies tunnelling of QSIG over the Session Initiation

19、Protocol (SIP). This enables calls between “islands“ of circuit switched networks that use QSIG signalling to be interconnected by an IP network that uses SIP signalling without loss of QSIG functionality. The present document facilitates the introduction of enhanced SIP and SDP functionality that w

20、as specified after publication of the early editions of the present document. These enhancements include payload encryption and mechanisms to negotiate SDP capabilities. The changes in the present document comprise a mandatory payload renegotiation with reversed direction of the offer/answer exchang

21、e compared with early editions. In order to achieve backward compatibility with early editions an indicator for the changed signalling procedures is introduced. This indicator is used to dynamically detect if fallback to signalling procedures compliant to early editions is necessary. The present doc

22、ument is based upon the practical experience of Ecma member companies and the results of their active and continuous participation in the work of ISO/IEC JTC1, ITU-T, IETF, ETSI and other international and national standardization bodies. It represents a pragmatic and widely based consensus. ETSI ET

23、SI TS 102 345 V1.3.1 (2008-10)61 Scope The present document specifies tunnelling of “QSIG“ over the Session Initiation Protocol (SIP) within a corporate telecommunication network (CN). “QSIG“ is a signalling protocol that operates between Private Integrated services Network eXchanges (PINX) within a

24、 Private Integrated Services Network (PISN). A PISN provides circuit-switched basic services and supplementary services to its users. QSIG is specified in Standards, in particular 1 (call control in support of basic services), 2 (generic functional protocol for the support of supplementary services)

25、 and a number of Standards specifying individual supplementary services. NOTE: The name QSIG was derived from the fact that it is used for signalling at the Q reference point. The Q reference point is a point of demarcation between two PINXs 1. SIP is an application layer protocol for establishing,

26、terminating and modifying multimedia sessions. It is typically carried over IP 4, 6. Telephone calls are considered as a type of multimedia session where just audio is exchanged. SIP is defined in 9. Often a CN comprises both PISNs employing QSIG and IP networks employing SIP. A call or call indepen

27、dent signalling can originate at a user connected to a PISN and terminate at a user connected to an IP network or vice versa. In either case, a gateway provides interworking between QSIG and SIP at the boundary between the PISN and the IP network. Basic call interworking at a gateway is specified in

28、 3. Another case is where a call or call independent signalling originates at a user connected to a PISN, traverses an IP network using SIP, and terminates at a user connected to another (or another part of the same) PISN. The present document addresses this last case in a way that preserves all QSI

29、G capabilities across the IP network. It achieves this by tunnelling QSIG messages within SIP requests and responses in the context of a SIP dialog. The tunnelling of QSIG through a public IP network employing SIP is outside the scope of the present document. However, the functionality specified in

30、thhe present document is in principle applicable to such a scenario when deployed in conjunction with other relevant functionality (e.g. address translation, security functions, etc.) The present document is applicable to any interworking unit that can act as a gateway between a PISN employing QSIG

31、and a corporate IP network employing SIP, with QSIG tunnelled within SIP requests and responses. 2 Normative references 1 ISO/IEC 11572: “Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Circuit mode bearer services - Inter-

32、exchange signalling procedures and protocol“ (also published by Ecma as Standard ECMA-143). 2 ISO/IEC 11582: “Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Generic functional protocol for the support of supplementary serv

33、ices - Inter-exchange signalling procedures and protocol “ (also published by Ecma as Standard ECMA-165). 3 ISO/IEC 17343: “Information technology - Telecommunications and information exchange between systems - Corporate telecommunication networks - Signalling interworking between QSIG and SIP - Bas

34、ic services“ (also published by Ecma as Standard ECMA-339). 4 IETF RFC 791: “Internet Protocol“. 5 IETF RFC 2119: “Key words for use in RFCs to Indicate Requirement Levels“. 6 IETF RFC 2460: “Internet Protocol, Version 6 (IPv6) Specification“. 7 IETF RFC 2976: “The SIP INFO Method“. 8 IETF RFC 3204:

35、 “MIME media types for ISUP and QSIG Objects“. 9 IETF RFC 3261: “SIP: Session Initiation Protocol“. ETSI ETSI TS 102 345 V1.3.1 (2008-10)710 IETF RFC 3264: “An Offer/Answer Model with the Session Description Protocol (SDP)“. 11 IETF RFC 3311: “The Session Initiation Protocol (SIP) UPDATE Method“. 12

36、 IETF RFC 3840: “Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)“. NOTE: Available at http:/tools.ietf.org/html/rfc3840 3 Terms and definitions In the present document, the key words “MUST“, “MUST NOT“, “REQUIRED“, “SHALL“, “SHALL NOT“, “SHOULD“, “SHOULD NOT“, “RECOMMENDE

37、D“, “MAY“, and “OPTIONAL“ are to be interpreted as described in 5 and indicate requirement levels for compliant SIP implementations. For the purposes of the present document, the following definitions apply. 3.1 External definitions The definitions in 1 and 9 apply as appropriate. 3.2 Other definiti

38、ons 3.2.1 Corporate telecommunication Network (CN) Sets of privately-owned or carrier-provided equipment that are located at geographically dispersed locations and are interconnected to provide telecommunication services to a defined group of users. NOTE: A CN can comprise a PISN, a private IP netwo

39、rk (intranet) or a combination of the two. 3.2.2 Egress gateway A gateway handling a QSIG call or call-independent signalling connection established in the direction IP network to PISN. 3.2.3 Gateway An entity that behaves as a QSIG Transit PINX with QSIG carried over a circuit-switched link within

40、a PISN on one side and QSIG tunnelled over SIP within an IP network on the other side. 3.2.4 Ingress gateway A gateway handling a QSIG call or call-independent signalling connection established in the direction PISN to IP network. 3.2.5 IP network A network, unless otherwise stated a corporate netwo

41、rk, offering connectionless packet-mode services based on the Internet Protocol (IP) as the network layer protocol. 3.2.6 Media stream Audio or other user information transmitted in UDP packets, typically containing RTP, in a single direction between the gateway and a peer entity participating in a

42、session established using SIP. NOTE: Normally a SIP session establishes a pair of media streams, one in each direction. ETSI ETSI TS 102 345 V1.3.1 (2008-10)83.2.7 Private Integrated Services Network (PISN) A CN or part of a CN that employs circuit-switched technology and QSIG signalling. 3.2.8 Priv

43、ate Integrated services Network eXchange (PINX) A PISN nodal entity comprising switching and call handling functions and supporting QSIG signalling in accordance with 1. 4 Abbreviations and acronyms CN Corporate telecommunication Network IP Internet Protocol PINX Private Integrated services Network

44、eXchange PISN Private Integrated Services Network QSIG Signalling system for the Q reference point RTP Real-time Transport Protocol SDP Session Description Protocol SIP Session Initiation Protocol TCP Transmission Control ProtocolTLS Transport Layer Security UA User Agent UAC User Agent Client UAS U

45、ser Agent Server UDP User Datagram Protocol URI Universal Resource Identifier 5 Background and architecture 5.1 Architecture The present document concerns the case of a call or call independent signalling that originates at a user connected to a PISN employing QSIG, traverses an IP network employing

46、 SIP, and terminates at a user connected to another (or another part of the same) PISN. This can be achieved by employing a gateway at each boundary between a PISN employing QSIG and an IP network employing SIP, as shown in figure 1. Figure 1: Call from QSIG via SIP to QSIG ETSI ETSI TS 102 345 V1.3

47、.1 (2008-10)9Each gateway can provide interworking as specified in 3. This provides a basic call capability. However, 3 only specifies interworking for QSIG basic call, as specified in 1. Many of the other capabilities of QSIG (support for supplementary services and additional network features) as s

48、pecified in other standards and in vendor-specific specifications are not covered. Some of these additional capabilities of QSIG are suitable for interworking with SIP and might be the subject of future Standards or other specifications. Other capabilities of QSIG are unsuitable for interworking wit

49、h SIP because corresponding capabilities do not exist in SIP or are achieved in ways that are incompatible with QSIG. Therefore interworking at a gateway between QSIG and SIP will be limited to those QSIG capabilities that have sufficiently compatible equivalents in SIP. Each capability requires special implementation in the gateway, and therefore a typical gateway might provide interworking for only a subset of capabilities for which interworking is feasible. The result of this is that there will be a loss of capa